Participants with the highest adherence to the intervention saw the most improvement
A new study in eClinicalMedicine, a member of the Lancet family of journals, assessed whether walnut consumption has beneficial effects on the neuropsychological and behavioral development of adolescents.
A six-month randomized controlled nutrition intervention trial was carried out in 12 high schools in Barcelona, Spain. A total of 771 healthy teenagers between 11 and 16 years of age were randomized into two groups. The intervention group received 30 g/day of raw walnut kernels to be incorporated into their diet for six months, while the control group followed their usual diet. Primary endpoints concerning neuropsychological development (working memory, attention, fluid intelligence and executive function) and behavioral development (socio-emotional and attention deficit hyperactivity disorder symptoms) were assessed at baseline and after the intervention. Levels of red blood cell alpha-linolenic acid —an omega-3 fatty acid found in walnuts— were determined at baseline and six months as a measure of compliance.
Although there were no statistically significant differences between the intervention and control groups in intention-to-treat analyses, there were differences in adherence-adjusted analyses. In other words, although being prescribed eating walnuts for six months did not improve neuropsychological function, a number of improvements —including in sustained attention, fluid intelligence and attention deficit hyperactivity disorder symptoms— were observed in the participants who better complied with the walnut intervention. This study provides valuable insights and a basis for future scientific research on the effect of walnuts on adolescent brain development.
The California Walnut Commission (CWC) supported this study by supplying the walnuts for free.
Pinar-Martí, A., Gignac, F., Fernández-Barrés, S. et al. (2023). Effect of walnut consumption on neuropsychological development in healthy adolescents: a multi-school randomised controlled trial. EClinicalMedicine, 59, 101954.